Solve for $a$ : $a + 25 = 6$
Explanation: Subtract $25$ from both sides: $ \begin{eqnarray} \\ a + 25 &=& 6 \\ \\ {-25} && {-25} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{25 + a} &\hphantom{=}& \hphantom{6} \\ a &=& 6 {- 25} \\ \end{eqnarray} $ Simplify. $ a = -19$